This invention relates in general to vehicle driveshafts, and in particular to a vehicle driveshaft tube having improved sound deadening properties.
Torque transmitting shafts are widely used for transferring rotational power between a source of rotational power and a rotatably driven mechanism. An example of a torque transmitting shaft is a driveshaft tube used in a vehicle driveshaft assembly. The driveshaft assembly transmits rotational power from a source, such as an engine, to a driven component, such as a pair of wheels.
A typical vehicle driveshaft assembly includes a hollow cylindrical driveshaft tube having an end fitting secured to each end thereof. Usually, the end fittings are embodied as end yokes which are adapted to cooperate with respective universal joints. For example, a driveshaft assembly of this general type is often used to provide a rotatable driving connection between the output shaft of a vehicle transmission and an input shaft of an axle assembly for rotatably driving the vehicle wheels.
One problem encountered by driveshaft tubes is their tendency to produce and transmit sound while transferring the power of the engine to the axle assembly. The sound can be undesirably noisy to passengers riding in the vehicle. Thus it would be advantageous to deaden or reduce the sound produced by a vehicle driveshaft tube, in order to provide the passengers with a more quiet and comfortable ride.
Various attempts have been made to deaden the sound produced by vehicle driveshaft tubes. In one such attempt, a hollow cylindrical cardboard insert was disposed inside an aluminum driveshaft tube to deaden the sound. However, the cardboard insert required external rubber ribs to prevent it from sliding inside the aluminum driveshaft tube, and as a result it was relatively complicated and expensive to employ. Other attempts at deadening the sound produced by driveshaft tubes have suffered from similar drawbacks and have not been totally satisfactory.
A solution to the sound problem is not straightforward. For instance, there are questions concerning what types of materials could be employed, and how the materials could be used with the driveshaft tube to deaden sound. The effects of different approaches on sound production are uncertain. Further, any solution to the sound problem would have to take into consideration the structure of the driveshaft tube having end yokes welded at the ends.
Thus, it would be desirable to provide a driveshaft tube that produces and transmits less sound during operation of the vehicle. It would particularly be desirable to provide an uncomplicated, inexpensive and effective method to deaden the sound of such a driveshaft tube.